The present invention relates to high voltage power supplies and in particular to an internally situated counterbalancing mechanism designed to facilitate access to the electrical components of the transformer enclosure.
High voltage power supplies are utilized in a number of medical applications, such as for computerized axial tomography x-ray techniques. The supplies are utilized to automatically and accurately control the x-ray tube voltage and emission in order to provide optimum tomographic quality.
Conventional voltage supplies of this type normally consist of two separate units. One unit is provided to control the output of the supply. The anode current and voltage to the x-ray tube are thus regulated and monitored, either by the x-ray operator or through computer programming. The second unit consists of a covered enclosure or tank which contains an oil immersed transformer and the electronic components associated therewith. The units are interconnected by means of wire leads.
Voltage supplies of this type are capable of generating an accurately regulated output on the order of 150 KV at 50 mils. In order to produce this magnitude of output, a large transformer mounted to a frame assembly within the enclosure is required. The frame and transformer weigh approximately 1200 lbs. The weight of the overall transformer enclosure, including oil, cover and electronics, is in the neighborhood of 2000 lbs. Thus, what is involved is a massive, bulky piece of apparatus, difficult to ship and especially with respect to the electronics within the transformer enclosure, difficult to service because this portion of the supply is not readily accessible.
In order to facilitate servicing of the electronic components situated within the transformer enclosure, these components may be mounted on a frame or support connected to the interior surface of the movable cover. However, the enclosure and particularly the cover therefor, must be quite sturdy in nature and the weight of this cover in conjunction with the weight of the electronic components mounted thereto is quite substantial. In fact, the enclosure cover and electronics weigh approximately 300 lbs. to 400 lbs. and thus an independent, external lifting mechanism, such as a small crane, is required to move the cover to provide access to the interior of enclosure. To facilitate movement of the cover, the exterior surface of the cover may be provided with rings or the like in order to permit attachment of the crane thereto. Because of the requirement of an external lifting mechanism, servicing of the electronic components within the transformer enclosure is an expensive and time consuming project.
It is, therefore, a prime object of the present invention to provide a high voltage power supply which incorporates, within the transformer enclosure, a counterbalancing mechanism to facilitate access to the electronic components therein and eliminate the necessity for independent external lifting apparatus.
It is another object of the present invention to provide a high voltage power supply with an internal counterbalancing mechanism which provides for balanced forces on the enclosure cover to prevent skewing thereof during movement.
It is a further object of the present invention to provide a high voltage power supply with an internal counterbalancing mechanism which requires no additional space within the enclosure for the operation thereof.
It is a further object of the present invention to provide a high voltage power supply with an internal counterbalancing mechanism wherein the mechanism is comprised of simple, inexpensive components which function reliably.
In accordance with the present invention, a high voltage power supply unit includes a transformer and the electronic components associated with the transformer. An oil containing enclosure is provided in which the transformer is situated. The enclosure has a cover movable between the first position, where the enclosure is closed and the second position, wherein the interior of the enclosure is accessible. A support, to which the electronic components are mounted, is connected to the cover and movable therewith. Means, situated within the enclosure and operably connected to the cover, are provided to facilitate movement of the cover between the first and second positions.
The movement facilitating means comprises a pair of planar counterbalancing members, each of which is movably mounted along a different one of the interior walls of the enclosure. Each of the counterbalancing members is operably connected to the enclosure cover by a pair of cables which cooperate with sheaves rotatably mounted to the enclosure wall. Means are also provided for retaining each of the counterbalancing members in a fixed position with respect to the wall adjacent thereto in order to prevent movement of the members during shipment of the enclosure.
The power supply set forth herein is disclosed as being utilizable in x-ray tomography. This function is described for illustrative purposes only and the present invention should not be construed as being limited to this particular application.